Dial-type measuring instruments

ABSTRACT

The present invention provides a dial-type measuring instrument comprising a geared multiplier mechanism intended to amplify the movements of a movable indicator member facing the dial, wherein the multiplier mechanism comprises a disk driven by the movable measuring member of the instrument and located opposite a toothed wheel which serves to control the movements of the indicator member and is coaxial with the disk, said toothed wheel being connected to the disk by means of at least two resilient constraining members.

T I Lmted States Patent [151 3,661,027 Gattesco 51 May 9, 1972 54]DIAL-TYPE MEASURING 3,359,819 12/1967 Veilette et al ..74/41 1 xINSTRUMENTS 3,208,298 9/1965 Pickles ..74/41 1 3,443,449 5/1969 Kotarski..74/4ll X [72] Inventor: Giovanni Gattesco, Crissier, Switzerland [73]Assignee: Tesa S.A., Renens, Switzerland i E -aminer Leonal-d Gel-in[22] Filed: May 21, 1970 Attorney-James M. l-leilman and Heilman &Heilman Appl. No.: 39,328

Foreign Application Priority Data June 18, 1969 Switzerland ..9283/69US. Cl .74/41l Int. Cl .Fl6h 57/10 Field of Search ..74/4l 1 ReferencesCited UNITED STATES PATENTS 3/l960 Bliss et al ..74/4l l [5 7] ABSTRACT4 Claims, 4 Drawing Figures PATENTEDM Y 9M2 8,661,027

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DIAL-TYPE MEASURING INSTRUMENTS This invention relates to dial-typemeasuring instruments comprising a geared multiplier mechanism intendedto amplify the movements of a movable indicator member facing the dialand more particularly, but not exclusively, to comparators and dialgauges. These instruments which are of great value because they permitrapid, accurate, and easy reading, nevertheless have the disadvantage ofbeing delicate because the gears of the multiplier mechanism breakrelatively easily when the movable measuring member of the instrumentarrives abruptly at the end of its travel or when it is moved by sharpblows.

Attempts have been made to reduce this weakness by introducing variousanti-shock systems between the movable measuring member and themultiplier mechanism. These systems which utilize elastic meansabsorbing the shock received by the movable measuring member, act in onedirection only and therefore their role is thus incomplete. Moreover,some of them use relatively fragile support members, such as pins andeyebolts.

With the aim of remedying these disadvantages, the present inventionprovides a dial-type measuring instrument comprising a geared multipliermechanism intended to amplify the movements of a movable indicatormember facing the dial, wherein the multiplier mechanism comprises adisk driven by the movable measuring member of the instrument andlocated opposite a toothed wheel which serves to control the move mentsof the indicator member and is coaxial with the disk, said toothed wheelbeing connected to the disk by means of at least two resilientconstraining members, of which the axes are located one on either sideof the common axis of the toothed wheel and the disk and located in aplane perpendicular to said common axis.

The accompanying drawings show by way of example two embodiments of theinvention.

FIG. 1 is a part sectional view of a first embodiment;

FIG. 2 is an enlarged detail of FIG. 1;

FIG. 3 is a detailed section of FIG. 2; and

FIG. 4 is an enlarged detail of a second embodiment.

The instrument shown in FIGS. 1 to 3 is a dial gauge comprising a sliderule 1 relative to which is displaced a slide or movable measuringmember 2, the slide rule 1 and the member 2 each having at one of theirends the conventional measuring contacts and jaws 3. To the movablemember 2 is fitted a dial indicator unit 4 wherein is rotatably mountedan indicator member 5 facing the dial 6. The movements of the indicatormember 5 are amplified by a geared multiplier mechanism 7 controlling apinion 8 integral with the indicator member 5, said mechanism beingdriven by a rack 9 fitted to the slide rule. The pinion 8 and themechanism 7 are mounted between plates 10 located in the unit 4.

The multiplier mechanism 7 comprises a pinion l l meshing with the rack9, this pinion 11 being coaxial and integral with a disk 12 rotatablymounted between the plates 10 and located opposite a toothed wheel 13freely rotatable between the plates 10, coaxial to the disk 12 and thepinion l1 and meshing with the pinion 8 of the indicator member 5. Thetoothed wheel 13 is slotted to provide two diametrically opposed arcuaterecesses 14 which are disposed opposite two similar recesses 15 made inthe disk 12. Between the disk 12 and the wheel 13 are placed twocompression springs 16 of which the sides are respectively located inpairs of facing recesses 14 and 15 and the ends of which are engaged onstuds 17 of stops 18 also located in the pairs of recesses 14 and 15 andsupported against the ends of these latter. The springs 16 and stops 18have substantially the same diameter and each spring 16 has a length anddiameter respectively greater than the length and height of the recesses14 and 15. Therefore, the springs 16 are guided laterally and retainedlongitudinally by the recesses 14 and 15 which maintain them undercompression, while the stops l8 ensure a regular support at the ends ofsaid springs. Consequently the springs 16 provide a flexible assemblywithout any play between the disk 12 and the wheel 13.

The instrument described functions as follows: when the movable member 2is moved along the slide rule 1, the pinion l1 meshed with the rack 9rotates and drives the disk 12 with which it is integral. The disk 12transmits its movement to the springs 16 which drive the wheel 13 andthe latter operates the pinion 8 and the indicator member 5. If themovable member 2 is subjected to sudden acceleration and deceleration,for example at the start or end of its travel or when moved by sharpblows, as a result of the inertia of the assembly of the indicatormember 5, pinion 8 and toothed wheel 13, this inertia being veryimportant due to the large acceleration or deceleration caused by thegreat multiplication of the system, the disk 12 driven by the pinion 11will rotate whereas the assembly of the toothed wheel 13, pinion 8 andindicator member 5 will not move. Thus the springs 16 will be compressedbefore transmitting the movement and will absorb a large part of theener gy thus preventing the breaking of the gears. Once this shockabsorption has been effected, the springs 16 will take up their originalposition and, if need be, transmit the movement to the toothed wheel 13,and consequently to the pinion 8 and indicator member 5.

The second embodiment shown in FIG. 4 is a gauge similar to that of FIG.1 and only the multiplier mechanism is shown. This mechanism comprises apinion l9 meshing with the rack (not shown) of the instrument, thispinion being coaxial and integral with a disk 20 mounted rotatablybetween the (not shown) plates of the dial-type indicator of theinstrument. The disk 20 is located facing a toothed wheel 21 rotatingfreely between the plates, coaxial to the disk 20 and meshing with thepinion (not shown) driving the indicator member of the dial-typeindicator.

The disk 20 has two symmetrical fixing points 22 and each consisting ofa radial finger 23 extending along the periphery of the disk 20 andprovided with a notch 24. The toothed wheel 21 comprises a toothed rim27 connected to a wheel 28 by two spokes 29 and also having twosymmetrical fixing points 25, each comprising a radial finger 26extending within the rim 27 and having a notch 32.

Between the disk 20 and toothed wheel 21 are placed two tension springs30 each having at their ends a fixing hook 31. Each spring 30 is fixedto the corresponding fingers of the wheel 21 and disk 20 by engagementof the hooks 3] in the notches 24 and 32. The length of the springs 30is such that when the springs are connected they are under tension.Under these conditions the springs form a flexible assembly, withoutplay between the disk 20 and the toothed wheel 21.

This second form of embodiment performs as previously, except thatduring the relative movement of the disk 20 and wheel 21, one of thesprings 30 tightens while the other relaxes.

While the two described embodiments each have two shock absorbingsprings this number can be increased. It is also possible to replacethese springs by flexible members of another type, for example rubbermembers.

The instrument according to the invention has an effective absorption ofthe forces to which gears of its dial-type indication system aresubjected; said absorption being effected in both directions of movementof the movable measuring member. In addition, there is no difficulty indimensioning these members in such a way as to obtain all the desiredrobustness and its manufacture and assembly are simple.

What we claim is:

1. A dial-type measuring instrument comprising a geared multipliermechanism intended to amplify the movements of a movable indicatormember facing the dial wherein the multiplier mechanism comprises a diskdriven by the movable measuring member of the instrument and locatedopposite a toothed wheel which serves to control the movements of theindicator member and is coaxial with the disk; said toothed wheel formedwith at least two recessed slots for respectively supporting the sidesof at least two compression elements, said disk also formed with atleast two similar slots for respectively supporting the other sides ofsaid compression elements; each said compression elements arerespectively engaged on disks including a short rod projecting from itscenter.

4. An instrument according to claim 3 wherein the disks are supported onthe end portions of said slots.

1 l I l

1. A dial-type measuring instrument comprising a geared multipliermechanism intended to amplify the movements of a movable indicatormember facing the dial wherein the multiplier mechanism comprises a diskdriven by the movable measuring member of the instrument and locatedopposite a toothed wheel which serves to control the movements of theindicator member and is coaxial with the disk; said toothed wheel formedwith at least two recessed slots for respectively supporting the sidesof at least two compression elements, said disk also formed with atleast two similar slots for respectively supporting the other sides ofsaid compression elements; each of said springs having one end engaginga stop on the toothed wheel and the other end engaging a stop on thedisk.
 2. An instrument according to claim 1 wherein said end portions ofsaid compression elements engage directly on the end portion of therecessed slots.
 3. An instrument according to claim 1 wherein the endsof said compression elements are respectively engaged on disks includinga short rod projecting from its center.
 4. An instrument according toclaim 3 wherein the disks are supported on the end portions of saidslots.